MICROBIALLY INFLUENCED CORROSION OF FE-BASED, NI-BASED, CU-BASED, AL-BASED, AND TI-BASED WELDMENTS

Weldments representative of a range of marine structural materials wer e exposed to a natural marine environment, which was known from previo us studies to induce microbially influenced corrosion (MIC). The natur al environment suits at a University of Delaware site on the Delaware Bay, Lewes, Delaware. Companion laboratory control tests were conducte d at the University of Tennessee in 0.2 mu m filtered Delaware Bay wat er and in synthetic seawater. The natural and control tests were condu cted with weldments in both creviced and noncreviced conditions. Open- circuit potentials (OCPs) and corrosion rates (polarization-resistance measurements and microscopic examinations) were evaluated for all tes ts. The weldments studied were: UNS S30403 (304L), UNS S31603 (316L), and UNS N08367 (AL-6XN) stainless steels; HY-80 and K 11576 (HSLA-80) low-alloy steels; alloy 400 M-Cu alloy; 90-10 Cu-Ni alloy; 5086 alumin um alloy; and unalloyed titanium.